Incandescent lamp with drawn-metal-wire filament.



K. .FARKAS. v

INGANDESCENT LAMP WITH DRAWN METAL WIRE FILAMBNT; uPLIgATIon IILED JUNE23, 1911.

1,008,809. Patented Nov. 14,;191 1.

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KARL FARKAS. OF GLEN RIDGE, JERSEY.

INCANDESCENT LAltIP WITH DRAWN-METAL-WIRE FILAMEN'IE i ,oossoo.

Application filed June 23,

To all 1137mm it may concern:

IQ it known that L Kain, Famus, a citizen oi" the Kingdom o't Hungary,and a resitlent o'l (ilen Ridge, county of Essex, and htateot NewJersev. have invented certain new and useful improvements inIncandescent Lamps with DrawteMetal-lYire Filaments of which thetollowing is a specification.

This invention has reference to improvements in metal filament lamps andpertains tnu'tieulartv to that type of lamps which are provided withdrawn metal wire filaments as an lllttttttltrt'ttit. Such drawn metalwire tilament may consist of one crmtinuous piece of tine wire which iswound successively and alternately over the insulated sttpports oranchors near the ends of the glass rod within'the lamp and connectedwith its ends to the two lends. This arrangement however is detectiveowing to the longitudinal expansion of the tine metal wire during theoperation of the latnp. \Vhen this tine wire is heated to incandeseenreit throughout its entire length to such a degree as to be undesirable orimpracticable. It is self-evident that the longitudinal expansion ofsuch a tine relatively longwire arranged in a rather limited space andpassing from anchor to anchor down to the leads where its ends arepermanently secured is such as to bulge out the single sections of thewire and press them too hard against the inner walls of the anchorloops.

It; is the special purpose ol' this lllVtlltlUtl to avoid the abovedescribed deficiencies of a drawn metal wire lamp and still retain thegood qualities of same without incratsing the cost of theirimtnutaeture. This has been primarily attained by .lividing the wirelength into two portions which has been rendered possible for practicalpurposes by the construction of a novel interior stem with a rod orarbor provided witlr a condur-tive means in the lower portion of the rodwhereby such division is effected. Aes cordingly there are two wirelengths within one lamp and the longitudinal expansion has been redu edto one half which answers the practical requiremtait in the manutactureof lamps with drawnmetal wire tilaments while the costly cementing ot'the single hair pin loops of the former metallie lilament lamps is alsoavoided in order to makethe in e a it entirely Specification of LettersPatent,

expands Patented Nov. 14, 1911.

1911. Serial No. 635,012.

drawing in which Figure 1 represents in elevation ifi'iftiip with drawnu'tetatwire filament embodying in desirable form the presentimprovements. Fig. shows in top plan view the upperpart of the rod orarbor, Fig. 3 is a like top plan view of the lower portion of said rodor arbor, and Fig. 4 illustrates in elevation somewhat in perspectiveview the lower po'rtion of the interior stem on an enlarged scale.

Similar characters of reference denote like parts in all the figures.

In the drawing in Fig. 1 (t represents the lamp globe. is the interiorstem. 0 the rod or arbor, (Z the drawn wire filament of a refractorymetal and c the lamp socket. The lamp is made, exhausted and tinishedinthe same mannt. as other lamps havingdrawn wire filaments of arefractory metal StiClt tungsten for instance. The tine drawn metal wirefilament. however eonsists of two set:-

clear reference is made to the accom mnying tions for the reasons abovestated. In orderto render possible the continuous passage of the currentthrough both portions of the filament the novel glass stem with rodshown in detail in Fig; 4 on an enlarged scale is provided. The hollowstem proper 7) has the usual solid glass portion 7) through which theleads f pass. The rod or arbor 0 made oi glass as usual is fused to thetop portion 1) of the stem l\ rim 1- is formed on the rod c right abovethe solid portion 6 of the stem Z). The rim supports a plurality ofanchors of even number which are insulated by the glass of the rim andmerely act as mechanical supports for the single sections of the drawnmetal wire. filament (Z.

A like rim i at the top of the rod supports a corresponding number ofinsulated anchors plus two, acting also solely as mechanical supports.

in order to divide the continuous filament into two portions il-1Ghorizontal auxiliary lead it. is fused into the rim 0 as shown. Thislead is preferably straight and has two tree ends so that there are newtour free ends for the tour free. ends of the two portions of the drawnwire filament, the two other free ends being the l ads proper f. The oneportion of the drawn wire filament starts at one lead ,1 and passessuccessively and alternately over three top anchors, two bottom anchorsand is secured to thcone tree end of the auxiliary lead. lhe currentthen may pass through the auxiliary lead into the second portion of thedrawn wire filament whose one end is secured to the second end of saidauxiliary lead. This second portion also passes over three top anchorsand two bottom ancho'rs while its second free end connects with thesecond lead proper thereby completing the circuit.

In the described manner the longitudinal expansion of the filament isreduced to one half in accordance with the division of the long'drawnwire filament into two portions preferably of equal length while thecostly cementing of the single hair pin loops is rendered unnecessaryand the deformation of the expanding filament is reduced to apractically permissible degree, leaving the single loops of each portionpractically straight during use. As above described and shown eachportion of the drip? wire filament consists of three loops. owever anyeven number of loops with necessary anchors may be provided accordingtorequirement, l

I claim as my invention 1. An incandescent lamp with drawn metal wirefilament divided into two portions comprising an interior stem withleads and rod, a rimon said rod near the stem, an auxiliary lead in saidrim, a plurality of insulated vanchors secured therein, and

.a corresponding number ofanchors plus two secured to the top of therod.

2. A metal wire filament lamp comprising an interior stem with leads androd, arim on said rod near the stem, an auxiliary lead in said rim, aplurality of. insulated anchors secured therein, and a metal wirefilament composed of two portions and supported by the anchors, eachportion being connected with one end to one lead proper and with theother to one end of the auxiliary lead.

3. A tungsten wire filament lamp comprising an interior stem with leadsand rod,

a rim on said rod near the stem, an auxiliary lead in said run to effecta division of the filament into two portions, a plurality of insulatedanchors secured therein, and a' corresponding'number of anchors plus twosecured to the top of the rod to connect with the ends of the auxiliarylead.

4. A tungsten wire filament lamp comprising an interior stem with leadsand rod, a rim on said rod near the stem, an auxiliary lead in said rim,a plurality of insulated anchors secured therein, and a drawn metal wirefilament composed of two portions and supported by the anchors, eachportion be ing connected with one end to one lead proper and with theother to one end of the auxiliary-leads I 5, In a tungsten Wire filamentlamp having a stem with leads, a glass rod or arbor fused to the stem, arim on said rod near the stem, an auxiliary lead in said rim, aplurality of insulzted anchors secuied there in, a rim at the of'therod, and a plurality of anchorsgigf like number plus two secured to saidto trim of the rod.

' 6. Ina tungsten wire filament lamp having a stem with leads and a rodfused thereto with a rim in its bottom and top portions, a horizontalauxiliary conductive lead in the bottom rim, a plurality of insulatedanchors of even number therein, a plurality of insulated anchors plustwo in the top rim, and a metal wire filament composed of two portions,the one portion being connected with one end to one lead'then assingover half the number of the top and ottom anchors and connecting withits second end to one end of the auxiliary lead, the second portionbeing connected with one end to the second end of the auxiliary leadthen passing over the remaining top and bottom anchors and connectingwith its second end to the second lead, thereby completing the circuit.

' Signed at New York, N. 1 this 22nd l/Vitnesses ConINNE MYnRs, VERAPAptsEN.

